(first of all, sorry for my bad english)
Ok, as you can see, i'm not an experienced user but I'm interested because (as you say rightly) many users have some problems... and me the same. But my problem was solved after reinstallation of SP 2. I run WinXP Pro and my original version (on cd-rom) was SP1.
Well, after SP2, many programs ran badly so I decided to reinstall all SP2... MAGIC!!!... all problems disappears. Have you troubles also with other software or only with Avast!
Thank you for your reply to my first ask.
Marco.